This is "newish" but still a TBI system, right? Not a transplant MPI (1991-up) motor with multi-point injection? Here are the details on the MAP sensor for a 1987-90 Jeep 2.5L TBI four: Jeep 2.5L TBI MAP Sensor Test.pdf I've included the cover illustration for your book search. These manuals have everything you need to know about troubleshooting, component tests and settings for the 2.5L TBI—and all other Jeep engines produced this model year (also applies to the range of 1987-90 Jeep models). A factory service manual from this period would be very helpful and authoritative. This is the level manual that I depend upon, and they are nearly always reliable and accurate. From 1991-up, the service books break down by model each year. XJ Cherokee and YJ Wrangler pair up, the Grand Cherokee (1992-up) and 1991 Grand Wagoneer have their own books. Later, the XJ Cherokee and TJ Wrangler books go separate ways. Try eBay or used book sources...I've chased down a factory workshop manual for every vehicle we've owned...I've purchased a new book or CD for the newer vehicles. These books are now available in CD version for later model vehicles, and this has driven down the cost substantially. Moses Jeep 2.5L TBI MAP Sensor Test.pdf
Speed, I have a methodical approach to testing out-of-chassis or in-chassis stationary engines. I've shared this in each of my books and many articles. You and others should find it helpful.
There are four "basics" to engine condition, and each needs attention. Here's how I would test the Toyota 22R four-cylinder OHC engine on the ground:
1) Compression or cylinder seal: This can be tested on the ground with a cylinder leakdown tester and an air compressor. Spark plugs removed, each piston must be brought to TDC on its compression stroke for an accurate read at the highest ring/cylinder wall wear point. If you don't have a leakdown tester, I describe how to simulate one at the General Repairs forum. The commercial testers have a gauge and the advantage of percentage leak readings. A leakdown test confirms piston ring, valve, head gasket and castings seal. Normal percentage of leak on a newer engine is 8%-10%. An engine will "run" okay at 20% leak. Beyond that, leak can affect manifold vacuum and the general engine performance. Cylinder balance is always assumed to be within 10% on a compression test; on a leakdown test, I like to see no more than 5%-7% cylinder leakage variance.
2) Oil pressure: This is difficult to test in a static engine but can be done. Using an oil pressure/priming tank, pressurize the engine's lubrication system to "normal" pressure. See if the engine bearings will hold that pressure. Since this 22R truck rolled over, be grateful it had carburetion and likely stalled. EFI engines have been known to run with the engine on its side or even upside down if the rollover switch does not function, resulting in bearing damage or seizure. If Brother Dutch did not hear any lower engine knocks, you may be okay...You'll know more when the engine is running. The best check is to drop the oil pan and pull the main and rod caps one at a time. Installing/rolling in new rod and main bearings is not a bad idea if the crankshaft is still round and mileage is somewhat high. Cleaning the oil sump screen and inspecting or replacing the oil pump is not a bad idea, either!
3a) Valve lift: This can be easily checked on an OHC engine like the Toyota 22R. Remove the valve cover and inspect the camshaft lobes and valve stem tips. With valves adjusted properly, use a 6" steel ruler to measure valve lift and the closing height at each valve. Compare the intake valves and the exhaust valves for lift. This is a rough but reasonably accurate test and easy to do on an OHC engine.
3b) Valve Timing: This is your question. Worn sprockets, chain and tensioner can retard valve timing. To test this, again have the valve cover off. Since there is a hydraulic chain tensioner, you will need oil pressure in the system to remove slack in the timing chain before checking the timing chain, guide and sprocket wear! See my notes below before proceeding...With the chain tensioner pressurized, slowly rotate the crankshaft in the normal direction of rotation and just bring the TDC mark up to "0" without passing TDC. Note the camshaft sprocket position. Now slowly rotate the crankshaft in the opposite (reverse) direction until the sprocket just starts to move. Note the degrees or distance the crank pulley has moved before the camshaft sprocket begins moving. Now rotate the crankshaft back toward TDC to confirm that the camshaft sprocket will begin to move at approximately the TDC point. I use a rough figure of 5/8" maximum pulley movement or slack/play on an 8" pulley to determine sprockets and chain wear. This is measured at the crankshaft pulley's outer edge and the timing cover markers. (On an engine without an overhead camshaft, the distributor rotor and crankshaft pulley can be a means for testing the timing chain wear. I share this information at the General Repairs forum, too.) Check the valve timing alignment points with the TDC mark. This is also telling with regard to chain, guide and tensioner face wear. When checking valve timing, always rotate the crankshaft in its normal direction of rotation and do not pass the TDC mark. Retarded valve timing is a sure sign of sprocket wear, chain stretch and/or chain guide and tensioner wear.
Note: Unless there is oil pressure, the stationary timing chain and tensioner check will not be accurate on an engine that has a hydraulic, oil pressure actuated tensioner (engines like the earlier Toyota 18RC four-cylinder engine or the Toyota 20R, 22R and RE engines). If you must test a stationary engine with a hydraulic chain tensioner like the Toyota 20R or 22R four-cylinder inline engines, try pressurizing the oil system with an oil priming tank. Set priming tank pressure to at least normal engine operating pressure.
Additional Toyota 20R/22R and 22RE timing chain and sprocket concerns: The 22R and 22RE are notorious for timing chain, chain guide and tensioner wear. The single roller chain is most troublesome, and this includes your '85 engine. The chain guides and tensioner surfaces wear out. Look for deep grooving in the guides, try to inspect the tensioner surface if viewable. Chain and sprocket wear is measureable. The chain should not exceed 147mm or 5.877" spacing between 17 links when the chain is pulled taut. This is impossible to measure with the engine assembled. The tensioner is more apt to wear its contact face than fail hydraulically, although the symptomatic rattle at startup that disappears when oil pressure rises is the timing chain/guides and tensioner before the tensioner takes up slack. Other measurements, including sprocket wear can be done, too. I can furnish dimensions, though this can only be measured with a new chain as a reference. Valve cover removed, look down the chain guides to inspect for wear. The chain gets looser as the guide grooves deepen.
4) Normal oil pressure: This is dependent upon bearing clearances and general wear, including the oil pump. On a stationary engine, oil pressure and bearing oil "bleed-off" could be tested with an oil priming tank set to normal oil pressure level or higher. Steadily prime the lubrication system and try to hold that pressure within the system. If there is rapid pressure bleed off, this could hint of excessive bearing clearances. Slower bleed should be considered normal. With pressure applied steadily from the tank, the engine bearings should hold some degree of pressure, although there will still be a continuous bleed-off at the valve train and the engine's lower end bearings.
Trust this is all helpful to those buying or testing used engines and needing to know the engine's condition before installation in the chassis...
If the rear U-joint yoke has been removed, the output shaft could move forward in the manner you describe. A brass drift punch and hammer, tapping at the recess in the output shaft end (avoid the threads!) could do it. The output would be driving either the pilot bearing shoulder or the bottom of the pilot bore against the input shaft. Worse case scenario, the pilot bearing cage might get damaged, but if so, you were likely replacing the pilot bearing anyway.
Do not drive the output shaft very far forward—parts misalignment could effect the rest of the disassembly. Once the front retainer and input assembly are moving, bring the output shaft back to its original position. You should be able to get the input assembly moving with very little effort, so tapping the output forward should not demand much movement.
Welcome to the forums, Michael! Here's the rundown on what you face with this swap...
1) If emissions are an issue, the 4.2L, especially if still carbureted, would be a retro engine and not acceptable for emission compliance in states with smog inspection. If you have a Mopar EFI conversion (preferably a second generation system with single rail FI patterned after the '97-up TJ Wrangler), you might be able to get by with an inspector willing to ignore (or ignorant of) the earlier 4.2L long block versus a 4.0L engine. This would still be an engine change from four- to six-cylinder, which requires a smog referee station in California.
2) The 2.5L bellhousing pattern is entirely different than the 4.2L. (See my article at: http://www.4wdmechanix.com/YJ-&-TJ-Jeep-Wrangler-Clutch-Replacement.html. This is a 2.5L with AX5 transmission in a 1987-90 YJ Wrangler.) You also have an AX5 manual transmission in the '97 TJ, which was only used with 4-cylinder engines. This is an issue, as the AX5 will not work with the AX15 bellhousing, so you'll be seeking an AX15 transmission and bellhousing. The flywheel for the 2.5L could work with your 4.2L crankshaft, I've used a resurfaced 2.5L flywheel on a 4.0L engine. You'd need the correct pilot bearing for the 4.2L crankshaft and use of a manual transmission.
4) The real kicker is the frame. Both the Jeep YJ Wrangler and Jeep TJ Wrangler use a different frame for the 2.5L engine versus the inline six-cylinder 4.2L or 4.0L engines. At the magazine, I show what it takes to modify the frame and install a 4.0L or 4.2L in a YJ Wrangler originally equipped with the 2.5L inline four: http://www.4wdmechanix.com/MIG-Welding.html. The same principle applies with a TJ Wrangler's 2.5L four versus 4.0L inline six-cylinder frame.
Aside from the emissions legality issue, unless you have welding and fabrication skills, this could be a major project. The difference is the location of the side/front motor mounts. The 2.5L frames have the mounts permanently welded further back on the frame rails. Whether this was an engineering upgrade or for ease of production, the two-frame production method is somewhat puzzling. On CJs, the inline 4-, inline 6- and V-8 engines could be accommodated with factory bolt-in frame/engine brackets and even a cross brace bar that bolted into position. Beginning with the YJ Wrangler, AMC/Jeep adopted the four- and inline six-cylinder frame approach. Chrysler continued this approach through the Jeep TJ Wrangler era.
As a point of interest, the welding and fabrication that you see in my article is overkill compared to the OE frame brackets. The basic brackets are Advance Adapters products, the additional, reinforcing steel plate is by yours truly. The vehicle is my son-in-law and daughter's, and I wanted the mounts and welding to be indestructible for off-road, hard four-wheeling. Welding process is MIG, in this case with ER70S-6 0.035" wire.
I'm very pleased that you found a cause and solution...
From your photos, the Crown bearing appears to be pressed fully onto the release bearing collar. It looks "hung up" at the end of the front bearing retainer sleeve. That must be the "step" interfering? Your bearing retainer must be smooth to the end of the sleeve, since the newest bearing works fine.
You're on the home stretch, Diamond Jr...Looks like the external slave cylinder is your way to go!
Hi, Papaobewon, thanks for posting your first topic! You have given us all an excellent opportunity to discuss the concerns around buying a used Jeep TJ Wrangler and aftermarket equipment.
There are many vehicles out there, as the TJ was extremely popular in its 1997-2006 production period. I'll describe some things to look at and question regarding this particular Jeep for sale. My intention is not to berate the vehicle or the individual offering this 1998 TJ Wrangler 2.5L Jeep for sale...
Here are two distinctly different Jeep TJ Wrangler profiles. At left, a hardcore trail runner does what you would expect—drives the hard trails and works the suspension thoroughly! At right, a very clean Jeep TJ Wrangler with hardtop boasts factory and mild aftermarket upgrades—for a very long life expectancy.
First, let me distinguish that a 2.5L YJ or TJ Wrangler has a different frame than the 4.0L six-cylinder frame. This is important if you decide that four-cylinder power is "not enough" for the weight or usage you have planned. With all of the accessories and add-ons that this Jeep features, the 4-cylinder engine is toting quite a package, so fuel efficiency will be only marginally better than a 4.0L six-cylinder model.
The 2.5L pushrod OHV engine is a great design, AMC's contribution that Chrysler carried forward until the introduction of the 2.4L high-tech engine. It does a good job when not taxed too much, and the axle gearing is 4.10/4.11:1 on these models with the larger case Dana 35 differential.
The transmission is an AX5, the lighter version of the AX designs yet with the right gearing for a four-cylinder engine. Six-cylinder models use the AX15, which does offer a higher torque rating. To use the AX5 with a six-cylinder engine, you would need an adapter. If you wanted to make that swap, the YJ or TJ Wrangler changeover involves relocating and building motor mounts because of the frame differences. (Click on the link to see my MIG welding project.) This includes differences in the location of the rear transmission mount as well, a lesser fix that involves the skid-plate/crossmember. For these reasons, it's very important to decide whether you want a four-cylinder versus a six-cylinder model at the onset.
In making that choice, there are a variety of motives. Some purposely buy a four-cylinder if they plan a V-8 and alternative transmission swap into the Jeep. Others believe the four-cylinder will get the job done and deliver better fuel efficiency, which it does to a degree—until the weight of the modified vehicle taxes the engine to the point of offsetting the fuel efficiency.
I'd like to draw attention to the performance curves of the 2.5L inline four versus the 4.0L inline six: The four develops its peak torque at a higher rpm, horsepower peaks at 5,400 rpm, a virtually unattainable speed under most driving conditions and surely not fuel efficient at that speed.
Compare the two engines and transmissions at: http://www.allpar.com/model/cj/specs.html. This is a 1997 Jeep TJ Wrangler spec readout, the same as the 1998 you're considering. Also noted is that some base models did not have power steering, I'm presuming this Jeep does? You need it.
As a footnote, even the 4.0L inline six has a stodgy torque rise in my view, peaking at 2,800 rpm. By contrast, the legendary 4.2L inline six that contributes its crankshaft to the 4.6L stroker motor build-ups reaches peak torque between 1,600 and 2,000 rpm, depending upon the year model. That's diesel-type torque and why the 4.6L stroker motor is so popular!
As for the off-road performance of the four-cylinder models, they do quite well. Gearing in low range makes the engine sufficient for the job, and the MPI (1991-up) version of the 2.5L fuel injection is quite stable in slow crawling.
I'll address each feature in the order you listed them in your post:
1) A rebuilt or remanufactured engine should have receipts. A remanufactured engine is sold as a long block or short block (without rebuilt cylinder head); the complete long block includes the cylinder head and is desired here. A rebuilt engine should have receipts for machine work as well as parts. We can discuss the details if receipts are available.
2) Since this is a four-cylinder model, it has the AX5 transmission as I described.
3) The description sounds good: a fresh engine, 138,000 miles, only 3,000 on the new engine. Black is an awkward color, draws heat and tends to oxidize faster. The peeling or "crazing" is not uncommon for a black vehicle exposed to a lot of sun or parked outside.
4) A 4-inch lift is common, the body lift is mild as is the motor lift; if done right, this is an asset for off-road use.
5) Swing-out tire carrier is a plus.
6) Aftermarket sound is nice if a quality system and installed properly; always concern about wiring during the installation, must be done right.
7) Tires and spare sound good, 31" is not radical, and the OEM 4.10/4.11 gears can tolerate this diameter tire well. Speedometer may have slight error if not corrected for the 31" tires, this can be remedied with a speedometer drive gear/tooth count change.
Note: It surprises me that there is this much suspension lift plus a body lift for only 31" diameter tires. A four-inch suspension lift will accommodate 33" tires, which would require a ring-and-pinion gear change to 4.56:1 or even 4.88:1 for restoring performance. Maybe this vehicle did have 33" tires at one point; otherwise, the combination chassis and body lift is actually excessive for 31" tires. (A two-inch suspension lift would be sufficient for 31" tires on a TJ Wrangler.) The 31x10.5 tires are likely on 8" rims, and that's really not much track width increase for the amount of lift. For this amount of lift, I would do a 10" rim with 33" tires to widen the track width and help restore the vehicle's center-of-gravity.
8) Adjustable track bar is desirable with a link-and-coil suspension lift. This allows precise alignment to eliminate axle offset or dog tracking. Suspension parts and axles need to match up and align when there is an aftermarket lift on link and coil suspension.
9) New shocks and stabilizer are a plus if "new" means quality replacement parts. Gas-charged shocks are preferred here, Bilstein or equivalent.
10) Long sway bar links needed to compensate for the 4-inch suspension lift.
11) Stronger control arms, if quality made, are a major improvement over the stamped steel OEM arms.
12) Cold air intake can improve performance. System should not permit exposure to water, however. Any open faced air filter should be kept away from the spray or slosh of water during stream crossings! Sucking water can cause engine hydro-locking and severe internal engine parts damage.
13) Quality fog lights can be useful for the trail; make sure they're quality with safe, proper wiring.
14) Same as windshield lights; great if done properly.
15) Diff guards are a real plus for off-roading in rocky terrain.
16) Full skid plates are a plus, too! This adds weight, though, and we're talking four-cylinder power in this case.
17) The security console is a real plus, especially when parking the vehicle with the top removed.
18) Okay on the tint if legal and visible. Not sure of the motive.
19) Receipts useful here. Quality parts should be verified. Is the clutch new, too? Flywheel new or re-surfaced? Should be included with an engine replacement or rebuild.
20) Hardtop, especially factory type, is a valuable accessory! These tops are expensive to purchase later, a hardtop has many advantages: weather protection, security, added value. Downside is weight, another tax on that 120 horsepower engine.
21) Undercoated frame can be okay. Is the vehicle at a climate without salted roads? If salted, inspect the chassis and body end to end for rust and any signs of body or frame rust exfoliation. Undercoating is great if applied for the right reasons—not to cover rust, though!
22) Clean title is a must...
23) Chipping paint is back to the black. If the price is right and you want to restore this vehicle cosmetically, you can do so.
Regarding your last questions, a MOAB sticker can be good or bad. I've been to Moab since the mid-'nineties and witnessed vehicles used moderately by responsible folks, and I have also seen vehicles pounded mercilessly and abused, even wrecked—often due to driver inexperience. That said, Moab does mean something—what it means depends upon the driving skill of the owner and which trails the Jeep took at Moab. The same applies to the Rubicon Trail, Fordyce, Sierra Trek and so forth.
Get underneath and inspect the Jeep end-to-end. The most critical and expensive areas are the frame and axles. Look for signs of collision repairs and trail damage, abuse and so forth. Aftermarket products like lift kits have "perishable" components such as urethane bushings, Heim joints and other pivot points. Drivelines are a source of trouble, and this Jeep TJ Wrangler should have a slip yoke eliminator (SYE) kit at the transfer case outlet to the rear driveline plus a CV-type rear driveshaft. If not, the rear driveshaft is at risk; U-joint life will be short, driveline vibration likely.
Look for signs of rock-sliding along the control arms and other symptoms of hard use. Look for scarred diff skid plates. See if the steering gear is loose by manually moving the pitman arm back and forth with the vehicle parked, its front wheels pointed straight ahead; drive the Jeep and feel for steering wander and suspension looseness. Signs of trail use are not, in themselves, a reason to pass up the vehicle; however, scarring and looseness do suggest the kind of use the vehicle has seen.
In addition to writing for the 4WD magazines, I wrote for Popular Hot Rodding and several other muscle car and high performance magazines in the 'eighties and 'nineties. My tech Q&A columns would often receive questions about purchasing a used muscle car or Corvette with "low mileage". If a muscle car had "only" 50,000 original miles, I would reply that this could potentially be 200 trips down a quarter-mile drag strip! For a 4WD trail vehicle, 138K miles could be many thousands of trail miles. Metaphor: The notorious Rubicon Trail is only 12 miles long. We can "do the math".
Although none of these comments are meant to discourage your purchase, a used trail vehicle is all about its history. Modified vehicles are typically intended for hard trail use, so you do need to adjust your purchase price to allow for any parts damage from trail pounding. I would test drive the vehicle with an ear toward axle/differential noises, transmission synchronizer noise and feel (including "jumping out of gear"), clutch and driveline response, plus the drivetrain play and sounds in 4WD low range.
Look closely at the front axle shaft joints in the steering knuckles. Steering knuckle ball-joints and steering linkage joints can be worn out by this mileage from a lot of trail crawling or oversized tires. Inspect the front brake calipers and rotors, they're visible. Look at the drivelines and check for worn U-joints, grease seepage and a torn boot. A major oil leak at the rear main seal can be a nuisance and ruin a clutch disk. Axle pinion shaft seals and the transfer case output seals are other areas to check.
Anticipate what you want to do with the Jeep and how the modifications impact your use—or dovetail with it. Also weigh the cost of outfitting a stone stock 1998 TJ Wrangler with these upgrades. Consider a stock vehicle with an extraordinary history, something like "driven on icy highways but never off-road," "driven only on graded gravel—occasionally," "used to get back and forth to work in the winter," "used to access a ski resort in the winter," "not sure what this lever position [4WD/low range] does, I've never used it" —fill in the blanks.
My brother-in-law found a 1999 Jeep TJ Wrangler, stone stock with 70K original miles, the auxiliary cloth top never installed, the hardtop never removed, the wheels and tires stock with one OEM tire replacement; the engine is a 4.0L with 3-speed 32RH automatic transmission—owned by a mature couple, they never went beyond a graded gravel road with the Jeep and used it primarily for basic highway transportation and winter driving. He paid $6500 for the Jeep. It is prime for any kind of personalization and modifications, virtually a "new" Jeep TJ Wrangler.
While this sounds extraordinary, it's not a Rubicon model. For "hardcore" wheeling, the Sport model could use a rear locker. (Note: Some non-Rubicon TJs actually have the Dana 44 rear axle with limited slip option.) There would be a need for a lift kit, 4" for 33" diameter tires. Then all of the other driveline, SYE and other modifications...The cost of parts—and labor if you sublet all of this work—must be considered.
It's not easy making these choices. The best way to approach this is as an "informed" buyer. I trust that these comments, the magazine and the forums help. I and many others can contribute additional comments and ideas, so please ask. It's for the benefit of everyone!